NEW YORK — The Standard&Poor's 500 index and Nasdaq composite index both reached four-year highs yesterday as investors, unfazed by oil prices nearing $60 per barrel, welcomed a raft of strong earnings reports.

The earnings, led by DaimlerChrysler AG and Bristol-Myers Squibb Co., further fueled investors' confidence in the stability of the economy. They also helped Wall Street look past a slight rise in first-time jobless claims reported by the Labor Department and another sharp rise in oil prices. A barrel of light crude settled at $59.94, up 83 cents, on the New York Mercantile Exchange.

The question on many investors' minds, however, was how high the markets can go, and whether the economy over the second half of the year will support those higher share prices.

"Obviously, we had a nice day yesterday, so now I tend to think that we're digesting all these earnings and figuring out whether we can move higher," said Jay Suskind, head trader at Ryan Beck & Co. "The news has been very good, but now the market's pricing in the second half of the year even more."

DaimlerChrysler surged 9.8 percent, or $4.29, to $48.26 after the company also posted slightly improved earnings. The stock was also helped by CEO Juergen Schrempp's announcement that he would leave by the end of the year.

Advancing issues outnumbered decliners by more than 5 to 2 on the New York Stock Exchange, where consolidated volume came to 2.06 billion shares, compared with 2.02 billion on Wednesday.